I am currently working on a watchkit app and ran into a problem with a flickering table.
The situation is as follows: With the storyboard tool, I created a table containing two row types.
The concept is, that when the data for the table is being downloaded, there is only one row of the first type which will use the whole space to indicate, that data is being downloaded. When the data arrives the second row type is used to display the data.
The problem is, that the table is somehow flickering, while it is being updated with the data. I was able to fix this problem by removing the download indication message und using only the one row type for data.
My question is, if someone did run into a similar problem or if there is any better way/pattern to display this kind of information messages, which show the user whats going on when he is using the app.
The WatchKit Table will flicker when reloading when a visible cell is different size than the other cells. Make sure they are all the same height and width and you will not have a flicker.
The way I did it was to put a group above my table that took up the entire screen with a loading animation inside it. I then hide/show the groups as needed.
Related
I need help identifying what piece of code is causing a bug in my app but having a hard time working it out.
So, my app is designed to display a detail screen for any row that is selected in the master table.
I have recently updated my app to use an NSFetchResultsController. The results are what I would expect except for one odd behaviour.
The new behaviour happens when I select a row in the master table, prior to the segue to the detail screen.
The table populates with all the data I would expect. But, on clicking any row in the table (other than the first one), each field in the row is set to the default values that appear in the storyboard.
The segue to the detail screen displays the expected details and the underlying database table is also correct.
I have a segue outlet action on the cell but no other method.
Despite placing breakpoints at various points in the code, I cannot identify which code section is triggering the setting of the row to the storyboard defaults.
I'd appreciate any steer that would help me work this out.
I posted my question as relative newbie to xCode. I've now discovered the profiling tools built into xCode and have been able to identify what's happening in my code with more confidence.
I already found entries with that topic on this page and also a website that provides a tutorial for that problem. But nothing worked very well.
The tutorial sad I should double the height of my tableView so cells loaded earlier, but with a higher tableView I never reached the last cells.
My problem is, I use a tableView to display my apps mainpage. This mainPage shows every time a topic and if its necessary for that topic it shows for example a cell with a map, one with pictures and sometimes not. Problem now, if I trying to scroll to my view its always lagging because it loads a map or this pictures. And scrolling back again because the loaded cells already deleted. I used a tableView because of the possibility to switch celltypes(mapCell, pictureCell, textCell) on and off.
I understand this feature, because of memory issues but in my case its not that much and it would be better if all my cells be preloaded and stay in memory until I change the topic.
Is there a swifty way to told my tableView to have this behavior?
Thanks a lot and nice greetings
I would suggest a different approach. Set up your table view controller to install placeholder images in your cells, trigger an async download that you cache to disk, and then update the cell with it's downloaded content if it's still visible when the download is finished.
There are various third party frameworks that do all this housekeeping for you.
Declare a cell array.
Follow these steps whenever change in your topic.
Clear you array
Create and configure all cells add to your array.
Return these cells to datasource methods using row index. Don't use tableview dequeue method here.
I'm new to IOS development, I have a few questions.
1) What's the purpose of property rowheight on table view cell, I mean it does nothing even if I change its value, it always takes the value from its parent view i.e a tableview property rowheight? It visually changes in the IB but nothing happens when I run the app.
2) What's the purpose of Content View why is it even there? Let's say If I have to make some image equal to the height of the cell it restricts me. Or is there any way a content view can be changed to be equal to the cell height & width? I have to put constraints on the image in relation with the cell which is not the immediate parent of the image and I don't know if this is the correct way to do it.
3)How does Xcode Autocomplete works? like if I want to write a function tableview(_:tableview didselectrowwithindex:IndexPath) and I type tableview it shows a list, what to do next? I mean I can't type the whole fucntion with params or find the func in the huge list.
The height of the cell set at the IB is primarily used for simulation, the views described at IB are normally resized when actually used. E.g. you can set rows height to be 100 for the table view, 30 for some of the cells and keep the whole controller simulating a nice screen of iPhone 6. The same view will be used for all devices and will be scaled accordingly as well as the cells with the help of your delegate.
The content view is there for the reasons directly related to your additional requests. It holds all the content while there other views that accompany your content and are part of the cell like separators, accessory views, slide action views. Without a content view the responsibility of managing all the additional parts would most likely fall on you as a developer and while you might think that that is fine at the simple layouts, a simple enhancement to it would make a huge impact.
Fuzzy autocompletion at Xcode seems to be something Apple is working on now. If you can't wait and find it too difficult to navigate through the list, there are Xcode plugins available that provide fuzzy autocompletion.
Answering the question in the topic:
example: tableview(_:tableview didselectrowwithindex:IndexPath)
if you write tableview it will show all the symbols that start with tableview. For functions, it will show all the functions sorted by the second parameter name (didSelectRowWithIndex).
[EDIT]
it will autocomplete as far as the answer is unique and then show you a list full of options. I don't know any tricks to skip looking through the massive list. But after a while you'll know what you're looking for and it gets faster.
[\EDIT]
when you press tab, it
by the way: the delegate functions names start with the name of the object they're related to.
So UITableViewDelegate functions start with tableview.
as for your first two questions there are tons of answers for those questions on SO. This one seems closely related to yours.
I have a master/detail app for iPad, with a few sliders on a table view cell to control the XYZ position of an image. Every time I add another cell, another image will show on the screen that can be moved around.
When the app is restarted the table view cells that I added disappear. I already have it set up to record and save the slider values to NSUserDefaults, but I want the cells to stay on the view. How can I save the cells, so they aren't deleted when the app is reloaded? I would also like to save the sliders' positions when the cells reload.
You probably need to add persistence to your app.
Some ideas to get you started are in this StackOverflow post.
You'll want to save the data for each of the cells, and recreate the cells when your TableView reloads upon app launch.
You can update the sliders with the stored values as well.
Posting the code you're using to do this, along with any issues, may help the community help you resolve this.
I am currently working on an iPad application that uses a table view to present data, I was inspired by the iTunes application in iPad that present it's data in multiple columns in a very nice and neat manner, and the most interesting thing is that during the portrait mode the itunes application displays data in 2 columns but when the user switches to landscape mode, it switches the display to 3 columns (since there are plenty of space to display data horizontally).
This is what i'm talking about:
but i found out that iOS SDK only supports single column for tableview (it would be nice to utilize the entire space provided on iPad screen to present data), i did some research and i found out that the best way to present data in multiple columns yet like spreadsheet style is to use datagridview instead, but iOS SDK did not provide any data grid view controls for iOS developers.
I found out over the internet some customized tables like:
AQGridView.
DTGridView.
and also the one from this:
http://usxue.is-programmer.com/posts/14176.html
and the one from this:
http://xebee.xebia.in/2011/04/14/building-editable-gridview-for-iphone-apps/
But sadly none of these ever met the requirements of the application i was working on.
Could you guys provide me some ideas or share some sample codes or links on how to display data in somehow-data grid view, to achieve similar effect used in iTunes application (as shown above).. Any form of help would be pretty much appreciated. Thank you guys!
The summary answer is, place multiple data "views" across in a single cell.
The more detailed answer:
Create custom views that represent the single cells you want. You can for this purpose make them resizable enough to work two across or three across (they will get loaded into 1/2 or 1/3 of the cells bounds).
Then make a custom UITableView cell, that can take two or three data items - load up an instance of the custom view previously created in the cell for each data item you have, placing them next to each other. You can have the cell do the view layout when groups of data items are added.
In the cellForRow code in the table delegate/datasource, you use your data source in groups of two or three (and report the row count accordingly) to pass along to the custom cell.
Sorry I can't share code, but I have used this technique before in other applications.
What's wrong with creating a UIView class to represent a single cell, and another that lays out an array of those cells in a grid? Put your grid view in a UIScrollView and you're about done.
UITableView is obviously a pretty complex class. Much of that is to make it very general, very reusable, and able to support a huge number of rows. Your class doesn't necessarily need to be that complicated -- if you have a fairly small number of cells, your "grid" could really just be a UIView in which you lay out cells in rows and columns. UITableView removes cells that aren't seen in order to save memory; you might need to do something similar if you have hundreds of cells, especially if they're large, but a few dozen probably won't require that.
In short, since you need a grid view for a particular use, you don't need to do all the extra work that would be required for a general, reusable solution.